Among the many causes of hearing loss, there may be mentioned in particular diseases such as meningitis or otitis, genetic causes, injuries, tumours, drugs, the administration of medicaments such as certain antibiotics, anti-cancer drugs, non-steroidal anti-inflammatory agents, diuretics, ulcer drugs or anticonvulsants, prolonged exposure to aromatic organic solvents such as toluene or xylene, ageing and exposure to noise. Presbycusis (age-related deafness), prolonged exposure to noise and the administration of medicaments are the main causes of hearing loss.
Today it is well known that certain antibiotics of the aminoglycoside family, such as gentamicin and tobramycin, which are used in the treatment of serious infections are responsible for cochlear deafness. The toxicity to aminosides (aminoglucosides such as amikacin, dibekacin, gentamicin, isepamicin, netilmicin, spectinomycin, tobramycin) initially expresses itself by an impairment of hearing at high frequencies and is not at first recognized by the patient. The latter will only gradually be bothered by this. Unfortunately it is often irreversible.
The noise around us lowers our hearing ability. Hearing loss caused by noise occurs when the acoustic hair cells which convey sound towards the inner ear are damaged and can no longer order the auditory nerve to send electrical pulses to the brain.
The volume of the sound and the duration of exposure are the two main factors influencing hearing loss. Although the reaction to exposure to noise varies from one person to the next, some facts can be reported with certainty. Research has shown that prolonged exposure to 85 decibels (dB) or more will, over time, cause permanent hearing loss.
European and North American statistics show that 8 to 10% of the population suffer from cochlear pathologies (deafness, tinnitus). Given the sound levels produced in discotheques, techno concerts and also by walkmans, a whole generation of deaf people and tinnitus sufferers is being created. Thus age-related problems (presbycusis) which these days start at around 60 years of age, could start much earlier, i.e. around 35-40 years of age.
The problem with auditory pathologies is that the great majority of them result from the loss of the acoustic hair cells and nerve cells of the inner ear (or cochlea). These cells, beyond a development phase which is essentially intra-uterine, do not have the ability to renew themselves after their last stage of differentiation.
The progressive loss of the sensitive and nervous powers of the ear related to different cochlear pathologies even today still appears to be beyond the scope of any treatment.